In recent years, there has been a tremendous resurgence of interest in the game of golf. This has been accompanied by a number of new designs of golf clubs all promising to lengthen drive, increase accuracy and turn duffers into professional quality players. Many of these promises have gone unfulfilled so the search continues for improved concepts which really perform.
I have been involved in the design of mechanical systems in which I have looked to basic fundamentals that often result in simplification, yet improved, performance. I can see that many of the attempts to design improved golf clubs may have merit, but it is my belief that some simple fundamental changes can produce a significantly better performing golf club.
There have been many attempts to enlarge the sweet spot of a clubhead. This has been done by enlarging the head in its entirety, and in certain cases, by distributing the volume of material to the edges of the clubhead. These attempts are designed to enlarge the sweet spot or, more precisely, to allow a slightly miss hit ball to have less effect upon the transfer of energy from the clubhead to the ball and to prevent twisting of the club in the hands of the golfer upon impact resulting in a hook or slice.
There is also an interest in avoiding twisting of the club in the hands of the golfer from too light a hold on the grip of the golf club. Yet, an excessively tight hold will result in tensing of arm muscles resulting in loss of control of the golf swing.
With the foregoing state of the art, I have recognized that different approaches can fill the need for enlarged sweet spot or improved performance in general.
Specifically, in one embodiment of my invention, I employ a hollow clubhead which has a plurality of individual chambers extending from the club face rearward through its body. Contained within each chamber are movable mass members which move subject to the force of the swing and the force upon impact with the ball. The force acting on the mass members during swing is principally centrifugal force and the force upon impact tends to drive the mass members into contact with the inside of the club face to transfer their kinetic energy to the club face at and shortly after the impact with the golf ball providing additional energy as well as absorbing undesirable vibrations. I have determined that it is desirable that the internal walls defining each one of the chambers be curved to conform with the arc of the swing.
I have also discovered that in connection with the movable weight within the clubhead that it is possible using an eccentric weight member of uniform, preferably threaded, exterior that the center of gravity of the weight and of the entire clubhead may be shifted to higher or lower positions in the head and actually farther forward or toward the rear of the clubhead.
In another embodiment of my invention, the clubhead is separable from the hosel and is adjustable in the angle of the head face. It also allows for the adjustment of a movable mass member located behind the face of the club, which concentrates the force of the club and also enlarges the sweet spot for greater accuracy. The mass member is preferably an aluminum cylindrical weight threaded into the body of the club and movable longitudinally parallel to the face of the club. With the readily separable hosel and clubhead, it is easy to attach a different shaft and hosel to the clubhead.
Once the mass member is adjusted to the desired position, it is not normally readjusted as the club is in use.
A modification of the above embodiment incorporates an internally adjustable weight member which can be readily adjusted by a golfer to fine tune the weight distribution of his club serving as an anti hook or slice device.
In my analysis of this invention, I have also discovered that even in apparently identical shafts made by the same manufacturer, the wall thickness of hollow shafts vary from as little as 0.004 in. to 0.014 in. at various positions around the shaft tube. This has a great effect on the stiffness and flexibility of the shaft. In other words, the shaft may respond quite differently depending on its orientation with respect to the face of the club. Therefore, I have provided a shaft attachment feature which allows a selection of angular orientation of the shaft head positions.
In order for the shaft to be properly attached to the head and for the weight positioning, as is described herein, within the head, I have produced a novel adjusting and locking tool which is also disclosed and claimed.
As a result of the development of the foregoing embodiments, the system of this invention provides:
a. interchangeable/quick detachable shafts;
b. totally adjustable center of gravity;
c. full range of adjustable loft;
d. adjustable lie; and
e. open or closed face adjustment options.
Additionally, for the manufacturer, it provides:
a. cost effective manufacturing;
b. major reduction in inventory including the same head for right or left handed players;
c. additional multiple shaft sales;
d. additional retrofitting after initial sale;
e. a precise custom fitting tool; and
f. most technologically advanced golf club offered.
For the user, it also provides:
a. custom fitting to give greater distance, accuracy, control and consistency;
b. a secure investment as the system can be reprogrammed as a golfer""s level of skill changes;
c. positive alternatives for the physically challenged; and
d. allows simple change of shaft by the user himself.